Additive manufacturing of hydroxyapatite and its composite materials: A review

2020 ◽  
Vol 05 (03) ◽  
pp. 2030002
Author(s):  
Chunze Yan ◽  
Gao Ma ◽  
Annan Chen ◽  
Ying Chen ◽  
Jiamin Wu ◽  
...  

Hydroxyapatite (HA) is a promising biomaterial for tissue engineering scaffolds due to its similar performance and composition to natural bone. However, the brittleness and poor toughness of pure HA limit its clinical application. Therefore, a lot of HA composites have been prepared to improve their mechanical performance. Fabricating complex and customized tissue engineering HA scaffolds have a very high requirement for manufacturing processes. It is difficult to fabricate ideal HA porous structures for artificial bone implants using traditional manufacturing processes, such as plasma spraying–sintering, and injection forming. Additive manufacturing (AM) could make three-dimensional physical parts with complex structures directly from computer-aided-design (CAD) models in a layer-by-layer way, and therefore show unique advantages in fabricating bone tissue engineering scaffolds with complex external shape and internal microporous structures. This paper reviews the state of the art for the preparation and AM process of HA and its composite materials, and raises the prospects for this research field.

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Alianna Maguire ◽  
Neethu Pottackal ◽  
M A S R Saadi ◽  
Muhammad M Rahman ◽  
Pulickel M Ajayan

Abstract Extrusion-based additive manufacturing (AM) enables the fabrication of three-dimensional structures with intricate cellular architectures where the material is selectively dispensed through a nozzle or orifice in a layer-by-layer fashion at the macro-, meso-, and micro-scale. Polymers and their composites are one of the most widely used materials and are of great interest in the field of AM due to their vast potential for various applications, especially for the medical, military, aerospace, and automotive industries. Because architected polymer-based structures impart remarkably improved material properties such as low density and high mechanical performance compared to their bulk counterparts, this review focuses particularly on the development of such objects by extrusion-based AM intended for structural applications. This review introduces the extrusion-based AM techniques followed by a discussion on the wide variety of materials used for extrusion printing, various architected structures, and their mechanical properties. Notable advances in newly developed polymer and composite materials and their potential applications are summarized. Finally, perspectives and insights into future research of extrusion-based AM on developing high-performance ultra-light materials using polymers and their composite materials are discussed.


Author(s):  
Neeraj Panhalkar ◽  
Ratnadeep Paul ◽  
Sam Anand

Additive manufacturing (AM) is widely used in aerospace, automobile, and medical industries for building highly accurate parts using a layer by layer approach. The stereolithography (STL) file is the standard file format used in AM machines and approximates the three-dimensional (3D) model of parts using planar triangles. However, as the STL file is an approximation of the actual computer aided design (CAD) surface, the geometric errors in the final manufactured parts are pronounced, particularly in those parts with highly curved surfaces. If the part is built with the minimum uniform layer thickness allowed by the AM machine, the manufactured part will typically have the best quality, but this will also result in a considerable increase in build time. Therefore, as a compromise, the part can be built with variable layer thicknesses, i.e., using an adaptive layering technique, which will reduce the part build time while still reducing the part errors and satisfying the geometric tolerance callouts on the part. This paper describes a new approach of determining the variable slices using a 3D k-d tree method. The paper validates the proposed k-d tree based adaptive layering approach for three test parts and documents the results by comparing the volumetric, cylindricity, sphericity, and profile errors obtained from this approach with those obtained using a uniform slicing method. Since current AM machines are incapable of handling adaptive slicing approach directly, a “pseudo” grouped adaptive layering approach is also proposed here. This “clustered slicing” technique will enable the fabrication of a part in bands of varying slice thicknesses with each band having clusters of uniform slice thicknesses. The proposed k-d tree based adaptive slicing approach along with clustered slicing has been validated with simulations of the test parts of different shapes.


Author(s):  
Ranjit Barua ◽  
Sudipto Datta ◽  
Amit Roychowdhury ◽  
Pallab Datta

Three-dimensional or 3D printing technology is a growing interest in medical fields like tissue engineering, dental, drug delivery, prosthetics, and implants. It is also known as the additive manufacturing (AM) process because the objects are done by extruding or depositing the material layer by layer, and the material may be like biomaterials, plastics, living cells, or powder ceramics. Specially in the medical field, this new technology has importance rewards in contrast with conventional technologies, such as the capability to fabricate patient-explicit difficult components, desire scaffolds for tissue engineering, and proper material consumption. In this chapter, different types of additive manufacturing (AM) techniques are described that are applied in the medical field, especially in community health and precision medicine.


Author(s):  
B. Li ◽  
T. Dutta Roy ◽  
C. M. Smith ◽  
P. A. Clark ◽  
K. H. Church

Numerous solid freeform fabrication (SFF) or rapid prototyping (RP) techniques have been employed in the field of tissue engineering to fabricate specially organized three-dimensional (3-D) structures such as scaffolds. Some such technologies include, but are not limited to, laminated object manufacturing (LOM), three-dimensional printing (3-DP) or ink-jet printing, selective laser sintering (SLS), and fused deposition modeling (FDM). These techniques are capable of rapidly producing highly complex 3-D scaffolds or other biomedical structures with the aid of a computer-aided design (CAD) system. However, they suffer from lack of consistency and repeatability, since most of these processes are not fully controlled and cannot reproduce the previous work with accuracy. Also, these techniques (excluding FDM) are not truly direct-print processes. Certain material removing steps are involved, which in turn increases the complexity and the cost of fabrication. The FDM process has good repeatability; however, the materials that can be used are limited due to the high temperature needed to melt the feedstock. Some researchers also reported that the scaffolds fabricated by FDM lack consistency in the z-direction. In this paper, we will present a true direct-print technology for repeatedly producing scaffolds and other biomedical structures for tissue engineering with the aid of our Computer Aided Biological (CAB) tool. Unlike other SFF techniques mentioned above, our direct-print process fabricates scaffolds or other complex 3-D structures by extruding (dispensing) a liquid material onto the substrate with a prescribed pattern generated by a CAD program. This can be a layer-by-layer 2.5 dimension build or a true 3-D build. The dispensed liquid material then polymerizes or solidifies, to form a solid structure. The flexibility in the types of materials that can be extruded ranges from polymers to living cells, encapsulated in the proper material. True 3-D structures are now possible on a wide range of substrates, including even in vivo. Some of the advantages of the process are a) researchers have full control over the patterns to be created; b) it is a true direct-print process with no material removing steps involved; c) it is highly consistent and repeatable; and d) it is highly efficient and cost-effective. This paper will first give a detailed description of the CAB tool. Then, it will present a detailed process for printing polycaprolactone (PCL) into a defined 3-D architecture, where the primary focus for these constructs is for use in tissue engineering applications. Finally, mechanical characterization results of the printed scaffolds will be included in the paper.


Author(s):  
Chuang Wei ◽  
Bhushan Sonawane ◽  
Lei Cai ◽  
Shanfeng Wang ◽  
Jingyan Dong

High-aspect-ratio three-dimensional structures using biocompatible materials are critical for tissue engineering applications. This study develops a multi-nozzle direct-write approach to construct tissue engineering scaffolds with complex three-dimensional structures utilizing polymeric materials. This approach provides the capability to fabricate three dimensional scaffolds by depositing biocompatible UV-curable polymeric material and thermoplastic material (paraffin wax) layer-by-layer, which respectively are used as structural material and supporting material that will be removed later on. The designed structure is built by selectively extruding drops and/or filament through a set of syringes that host different functional materials, following a layer-by-layer sequence. The location of the deposition is precisely controlled by a high precision three-dimensional translational stage. After different structural/functional materials and the supporting material are deposited with predesigned pattern, the supporting material is removed by using appropriate chemical solvent which will not affect physical and chemical properties of the designed structure. The mechanical property of the structure, the equilibrium modulus and dynamic stiffness, can be engineered by designing different pore size for the scaffold. The multi-nozzle based direct writing approach provides a practical solution to build scaffolds for tissue engineering and integrate multiple functional materials together into a single scaffold structure.


2019 ◽  
Vol 34 (6) ◽  
pp. 415-435 ◽  
Author(s):  
Tang Mei Shick ◽  
Aini Zuhra Abdul Kadir ◽  
Nor Hasrul Akhmal Ngadiman ◽  
Azanizawati Ma’aram

The current developments in three-dimensional printing also referred as “additive manufacturing” have transformed the scenarios for modern manufacturing and engineering design processes which show greatest advantages for the fabrication of complex structures such as scaffold for tissue engineering. This review aims to introduce additive manufacturing techniques in tissue engineering, types of biomaterials used in scaffold fabrication, as well as in vitro and in vivo evaluations. Biomaterials and fabrication methods could critically affect the outcomes of scaffold mechanical properties, design architectures, and cell proliferations. In addition, an ideal scaffold aids the efficiency of cell proliferation and allows the movements of cell nutrient inside the human body with their specific material properties. This article provides comprehensive review that covers broad range of all the biomaterial types using various additive manufacturing technologies. The data were extracted from 2008 to 2018 mostly from Google Scholar, ScienceDirect, and Scopus using keywords such as “Additive Manufacturing,” “3D Printing,” “Tissue Engineering,” “Biomaterial” and “Scaffold.” A 10 years research in this area was found to be mostly focused toward obtaining an ideal scaffold by investigating the fabrication strategies, biomaterials compatibility, scaffold design effectiveness through computer-aided design modeling, and optimum printing machine parameters identification. As a conclusion, this ideal scaffold fabrication can be obtained with the combination of different materials that could enhance the material properties which performed well in optimum additive manufacturing condition. Yet, there are still many challenges from the printing methods, bioprinting and cell culturing that needs to be discovered and investigated in the future.


Author(s):  
Henrique A. Almeida ◽  
Paulo J. Bártolo

Additive manufacturing technologies are being used to fabricate scaffolds with controlled architecture for tissue engineering applications. These technologies combined with computer-aided design systems enable to produce three-dimensional structures layer-by-layer in a multitude of materials. Actual prediction of the effective mechanical properties of scaffolds produced by Additive manufacturing systems, is very important for tissue engineering applications. One of the existing computer based techniques for scaffold design is topological optimisation. The goal of topological optimisation is to find the best use of material for a body that is subjected to either a single load or a multiple load distribution. This paper proposes a topological optimisation scheme based on existing micro-CT data in order to obtain the ideal topological architectures of scaffolds, maximising its mechanical behaviour under shear stress solicitations. This approach is based on micro-CT data of real biological tissues to create the loading (shear stress) and constraint surfaces of the scaffold during the topological optimisation process. This particular topological optimisation scheme uses the surface boundaries to produce novel models with different characteristics, which are different from the initial micro-CT models. This approach enables to produce valid biomimetic scaffold topologies for tissue engineering applications.


Author(s):  
Ranjit Barua ◽  
Sudipto Datta ◽  
Amit Roychowdhury ◽  
Pallab Datta

Three-dimensional or 3D printing technology is a growing interest in medical fields like tissue engineering, dental, drug delivery, prosthetics, and implants. It is also known as the additive manufacturing (AM) process because the objects are done by extruding or depositing the material layer by layer, and the material may be like biomaterials, plastics, living cells, or powder ceramics. Specially in the medical field, this new technology has importance rewards in contrast with conventional technologies, such as the capability to fabricate patient-explicit difficult components, desire scaffolds for tissue engineering, and proper material consumption. In this chapter, different types of additive manufacturing (AM) techniques are described that are applied in the medical field, especially in community health and precision medicine.


2021 ◽  
Vol 7 (2) ◽  
pp. 188-195
Author(s):  
Dong-Gyu Ahn

In recent years, additive manufacturing (AM) processes have emerged as an important manufacturing technology for a multi-item small sized production to lead the 4th industrial revolution. The layer-by-layer deposition characteristics of AM process can rapidly produce physical parts with three-dimensional geometry and desired functionality in a relatively low cost environment. The goal of this paper is to investigate the applicability of AM process to appropriate technologies for developing countries. Through the review of examples of appropriate technology of the AM process, the possibility of a practical usage of the AM process for the appropriate technologies is examined. In addition, significant applications of the AM process to the appropriate technology are introduced. Finally, future issues related to production of physical parts for developing countries using the AM process are discussed from the viewpoint of the appropriate technology.


2018 ◽  
Vol 9 ◽  
pp. 204173141880209 ◽  
Author(s):  
Patrick Rider ◽  
Željka Perić Kačarević ◽  
Said Alkildani ◽  
Sujith Retnasingh ◽  
Mike Barbeck

Bioprinting is the process of creating three-dimensional structures consisting of biomaterials, cells, and biomolecules. The current additive manufacturing techniques, inkjet-, extrusion-, and laser-based, create hydrogel structures for cellular encapsulation and support. The requirements for each technique, as well as the technical challenges of printing living cells, are discussed and compared. This review encompasses the current research of bioprinting for tissue engineering and its potential for creating tissue-mimicking structures.


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